1. Field of the Invention
The present invention relates in general to latch devices, and particularly to latch devices of a type which latches a pivotal member. More specifically, the present invention is concerned with a latch device for latching an inclinable back rest cushion which is pivotally mounted in a rear seat seatback of a passenger motor vehicle to provide, when folded, a tunnel between a passenger room and a trunk room.
2. Description of the Prior Art
Hitherto, various latch devices of the above-mentioned type have been proposed and put into practical use particularly in the field of passenger cars.
In order to clarify the task of the present invention, two conventional latch devices will be outlined, which are disclosed in Japanese Utility Model First Provisional Publication No. 59-190635 and Japanese Patent First Provisional Publication No. 59-149833.
In the device of Publication No. 59-190635, a striker is fixed to a vehicle body, and a hook engageable with the striker is mounted to the inclinable back rest. A push button is mounted on the back rest to actuate the hook. A pull strap extends from the push button and is exposed to the passenger room. When the pull strap is pulled from the passenger room, the push button is moved and thus the hook is actuated to release the engagement with the striker. A latch slider operable from the trunk room is incorporated with the push button to disable the same from moving. Once the latch slider assumes its operative position, the push button does not move even when the pull strap is pulled. Thus, under this, the latched engagement between the hook and the striker is not released.
In the device of Publication No. 59-149833, a striker is fixed to an inclinable back rest, and a hook is mounted to a vehicle body. A handle member is pivotally mounted on the vehicle body to actuate the hook. An operation lever operable from a trunk room is incorporated with the handle member. A connecting member is incorporated with the handle member and actuated by the operation lever. When, with manipulation of the operation lever, the connecting member is moved to a given position relative to the handle member, manipulation of the handle member actuates the hook in a direction to cancel the latched engagement between the hook and the striker. When, due to manipulation of the operation lever, the connecting member is moved to another given position, manipulation of the handle member does not actuate the hook. Thus, under this condition, the latched engagement between the hook and the striker is not released.
However, due to their inherent constructions, the above-mentioned conventional latch devices have the following drawbacks:
That is, in the device of Publication No. 59-190635, it is inevitably necessary to increase the mechanical strength of the push button and parts directly incorporated therewith and thus enlarge the size of them in order to stand against a big force applied thereto through the pull strap. In fact, when, for example, a child on a rear seat pulls the pull strap strongly just for fun, a big stress is applied to the push button and its incorporated parts. As is known, increase in size and strength of the parts induces a bulky and high cost construction of the lock device.
In the device of Publication No. 59-149833, the problems encountered in the above-mentioned conventional device are solved because of usage of a so-called "air striking mechanism". However, due to numerous parts including the hook, the handle member, the connecting member and operation links which are installed in the device, the construction of the same is complicated and cost of the same is increased.